1. Technical Field
The present invention relates to designing and fabricating devices that incorporate voltage switchable dielectric materials.
2. Description of Related Art
A printed circuit board, printed wiring board, integrated circuit (IC) package, or similar substrate (hereinafter, PCB) may be used to assemble and connect electronic components. A PCB typically includes a dielectric material and one or more conductive leads to provide electrical conductivity among various attached components, chips, and the like. Leads may be metallic, and are often formed using lithographic techniques (e.g., as a layer of Cu which is subsequently etched)
Various components may be attached to a PCB. Attachment may include soldering (e.g., reflowing), wire bonding, ultrasonic bonding, and the like. For applications requiring the attachment of several components to a PCB, the available “attachment area” on a surface of the PCB may limit the size and/or number of components that may be attached. Reducing the size of (and thus the surface area occupied by) an attached component may yield increased remaining area on the PCB surface, which may be used for attaching further components or larger components.
Various electrical and electronic components may benefit from surge protection, protection against electrostatic discharge (ESD) and protection against other spurious electrical events. ESD protection may include incorporating a voltage switchable dielectric material (VSDM). A VSDM may behave as an insulator at a low voltage, and a conductor at a higher voltage. A VSDM may be characterized by a so-called “switching voltage” between these states of low and high conductivity. A VSDM may shunt (e.g., to a ground) current that would otherwise damage a component by becoming conductive at voltages above the switching voltage and allowing currents at these voltages to pass to ground through the VSDM, rather than through the device being protected.
Some PCB components may be protected against electrical surges by attaching a surge protection device (e.g., a device incorporating a VSDM). In such cases, an attached surge-protection device may take up “attachable” regions (e.g., surface area) of the assembly. In such cases, minimizing the area of the device (while meeting requisite properties) may increase the available area for attachment of other components and/or minimize the overall size of the PCB assembly.